Characterization of a TiO2 photocatalyst synthesized by the solvothermal method and its catalytic performance for CHCl3 decomposition

It is considered that the solvothermal method in this study renders a reliable synthesis procedure of the TiO2 photocatalyst having the anatase structure of nano size. Two kinds of TiO2 photocatalysts were synthesized by using the sol-gel and solvothermal methods, and then their physical properties and catalytic performances were compared. The TiO2 powder (Cat. 2) obtained by the solvothermal method at 300 degreesC exhibited a pure anatase structure without any further treatment, while the TiO2 powder (Cat. 1) prepared by the sot-gel method was transformed to the anatase structure after thermal treatment at 500 degreesC for 3 h. Cat. 2 had higher surface area (121 m(2)/g) and surface charge (+24.1 mV) than Cat. 1 (51 m(2)/g, + 16.4 mV). In addition, the activation energy for H2O desorption over Cat. 2 was very high. These results show that the surface of Cat. 2 is very hydrophilic. In chloroform (CHCl3) decomposition under the UV-light (254 nm, 24 W/m(2)) with O-2 bubbling (500 ml/min), the catalytic performance of Cat. 2 was considerably higher than that of Cat. 1. More than 95% of the chloroform was decomposed in 2 h over Cat. 2. (C) 2001 Elsevier Science B.V. All rights reserved.